add some tests

experimental/babel-preset-env/src/transformPolyfillRequirePlugin.js

@@ -2,14 +2,8 @@
 // or if more than one is found
 
 const polyfillSource = "babel-polyfill";
-let numPolyfillImports = 0;
 
 export default function ({ types: t }) {
-  function checkNumPolyfillImports() {
-    numPolyfillImports++;
-    return numPolyfillImports > 1;
-  }
-
   function addImport(polyfill) {
     let declar = t.importDeclaration([], t.stringLiteral(`core-js/modules/${polyfill}`));
     declar._blockHoist = 3;
@@ -41,7 +35,8 @@ export default function ({ types: t }) {
     ImportDeclaration(path, state) {
       if (path.node.specifiers.length === 0 &&
           path.node.source.value === polyfillSource) {
-        if (checkNumPolyfillImports()) {
+        this.numPolyfillImports++;
+        if (this.numPolyfillImports > 1) {
           path.remove();
           return;
         }
@@ -53,19 +48,19 @@ export default function ({ types: t }) {
     Program(path, state) {
       if (!state.opts.polyfills) {
         throw path.buildCodeFrameError(`
-"polyfills" option not correctly passed
-to the transform-polyfill-require plugin
-in babel-preset-env
+There was an issue in "babel-preset-env" such that
+the "polyfills" option was not correctly passed
+to the "transform-polyfill-require" plugin
 `);
       }
       path.get("body").forEach((bodyPath) => {
         if (isRequire(bodyPath, polyfillSource)) {
-          if (checkNumPolyfillImports()) {
+          this.numPolyfillImports++;
+          if (this.numPolyfillImports > 1) {
             path.remove();
             return;
           }
 
-
           let requires = state.opts.polyfills.map((p) => addRequire(p));
           bodyPath.replaceWithMultiple(requires);
         }
@@ -75,6 +70,9 @@ in babel-preset-env
 
   return {
     name: "transform-polyfill-require",
-    visitor: isPolyfillImport
+    visitor: isPolyfillImport,
+    pre() {
+      this.numPolyfillImports = 0;
+    }
   };
 }

experimental/babel-preset-env/test/fixtures/preset-options/use-builtins-chrome-55/actual.js

@@ -1 +0,0 @@
-1 ** 2;

experimental/babel-preset-env/test/fixtures/preset-options/use-builtins-chrome-55/expected.js

@@ -1 +0,0 @@
-1 ** 2;

experimental/babel-preset-env/test/fixtures/preset-options/use-builtins-import/actual.js

@@ -0,0 +1,2 @@
+import "babel-polyfill";
+1 ** 2;

experimental/babel-preset-env/test/fixtures/preset-options/use-builtins-import/expected.js

@@ -0,0 +1,8 @@
+import "core-js/modules/es6.typed.data-view";
+import "core-js/modules/es6.reflect.apply";
+import "core-js/modules/es6.reflect.own-keys";
+import "core-js/modules/es6.symbol.iterator";
+import "core-js/modules/es6.symbol.species";
+import "core-js/modules/es6.array.from";
+
+1 ** 2;

experimental/babel-preset-env/test/fixtures/preset-options/use-builtins-import/options.json

@@ -2,7 +2,7 @@
   "presets": [
     ["../../../../lib", {
       "targets": {
-        "chrome": 54
+        "chrome": 55
       },
       "modules": false,
       "useBuiltIns": true

experimental/babel-preset-env/test/fixtures/preset-options/use-builtins-multiple-imports/actual.js

@@ -0,0 +1,3 @@
+import "babel-polyfill";
+import "babel-polyfill";
+1 ** 2;

experimental/babel-preset-env/test/fixtures/preset-options/use-builtins-multiple-imports/expected.js

@@ -0,0 +1,8 @@
+import "core-js/modules/es6.typed.data-view";
+import "core-js/modules/es6.reflect.apply";
+import "core-js/modules/es6.reflect.own-keys";
+import "core-js/modules/es6.symbol.iterator";
+import "core-js/modules/es6.symbol.species";
+import "core-js/modules/es6.array.from";
+
+1 ** 2;

experimental/babel-preset-env/test/fixtures/preset-options/use-builtins-multiple-imports/options.json

@@ -0,0 +1,11 @@
+{
+  "presets": [
+    ["../../../../lib", {
+      "targets": {
+        "chrome": 55
+      },
+      "modules": false,
+      "useBuiltIns": true
+    }]
+  ]
+}

experimental/babel-preset-env/test/fixtures/preset-options/use-builtins-require/actual.js

@@ -0,0 +1,3 @@
+require("babel-polyfill");
+
+1 ** 2;

experimental/babel-preset-env/test/fixtures/preset-options/use-builtins-require/expected.js

@@ -0,0 +1,13 @@
+require("core-js/modules/es6.typed.data-view");
+
+require("core-js/modules/es6.reflect.apply");
+
+require("core-js/modules/es6.reflect.own-keys");
+
+require("core-js/modules/es6.symbol.iterator");
+
+require("core-js/modules/es6.symbol.species");
+
+require("core-js/modules/es6.array.from");
+
+1 ** 2;

experimental/babel-preset-env/test/fixtures/preset-options/use-builtins-require/options.json

@@ -0,0 +1,11 @@
+{
+  "presets": [
+    ["../../../../lib", {
+      "targets": {
+        "chrome": 55
+      },
+      "modules": false,
+      "useBuiltIns": true
+    }]
+  ]
+}